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Commit 81fc0390 authored by Catalin Marinas's avatar Catalin Marinas Committed by Pekka Enberg
Browse files

kmemcheck: Test the full object in kmemcheck_is_obj_initialized() 



This is a fix for bug #14845 (bugzilla.kernel.org). The update_checksum()
function in mm/kmemleak.c calls kmemcheck_is_obj_initialised() before scanning
an object. When KMEMCHECK_PARTIAL_OK is enabled, this function returns true.
However, the crc32_le() reads smaller intervals (32-bit) for which
kmemleak_is_obj_initialised() may be false leading to a kmemcheck warning.

Note that kmemcheck_is_obj_initialized() is currently only used by
kmemleak before scanning a memory location.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Casteyde <casteyde.christian@free.fr>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
parent 724e6d3f

arch/x86/mm/kmemcheck/kmemcheck.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -337,7 +337,7 @@ bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size) 
	if (!shadow)

	if (!shadow)

		return true;

		return true;





	status = kmemcheck_shadow_test(shadow, size);

	status = kmemcheck_shadow_test_all(shadow, size);





	return status == KMEMCHECK_SHADOW_INITIALIZED;

	return status == KMEMCHECK_SHADOW_INITIALIZED;

}

}

arch/x86/mm/kmemcheck/shadow.c

+14 −2
Original line number Original line Diff line number Diff line
@@ -125,12 +125,12 @@ void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n) 




enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)

enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)

{

{

#ifdef CONFIG_KMEMCHECK_PARTIAL_OK

	uint8_t *x;

	uint8_t *x;

	unsigned int i;

	unsigned int i;





	x = shadow;

	x = shadow;





#ifdef CONFIG_KMEMCHECK_PARTIAL_OK

	/*

	/*

	 * Make sure _some_ bytes are initialized. Gcc frequently generates

	 * Make sure _some_ bytes are initialized. Gcc frequently generates

	 * code to access neighboring bytes.

	 * code to access neighboring bytes.
@@ -139,13 +139,25 @@ enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) 
		if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)

		if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)

			return x[i];

			return x[i];

	}

	}



	return x[0];

#else

#else

	return kmemcheck_shadow_test_all(shadow, size);

#endif

}



enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, unsigned int size)

{

	uint8_t *x;

	unsigned int i;



	x = shadow;



	/* All bytes must be initialized. */

	/* All bytes must be initialized. */

	for (i = 0; i < size; ++i) {

	for (i = 0; i < size; ++i) {

		if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)

		if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)

			return x[i];

			return x[i];

	}

	}

#endif





	return x[0];

	return x[0];

}

}

arch/x86/mm/kmemcheck/shadow.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -11,6 +11,8 @@ enum kmemcheck_shadow { 
void *kmemcheck_shadow_lookup(unsigned long address);

void *kmemcheck_shadow_lookup(unsigned long address);





enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size);

enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size);

enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow,

						unsigned int size);

void kmemcheck_shadow_set(void *shadow, unsigned int size);

void kmemcheck_shadow_set(void *shadow, unsigned int size);





#endif
 
#endif